Apparatus for coating a body such as printing cylinders with a light sensitive coating



06L 1965 E. SCHRODERSECKER 3,209,723

APPARATUS FOR COATING A BODY SUCH AS PRINTING CYLINDERS WITH A LIGHT SENSITIVE COATING Filed Jan. 29, 1962 F76. LIFTING APPARATUS 1 i 1 1 i l 2, 2' I I If 4 I l a 1 United States Patent 3,209,723 APPARATUS FOR COATING A BODY SUCH AS PRINTING CYLINDERS WITH A LIGHT SENSI- TIVE COATING Emil Sehro'dersecker, Neue Bahnhofstrasse 13, Neu Edingen Post Mannheim-Friedrichsfeld, Germany Filed Jan. 29, 1962, Ser. No. 169,251 Claims priority, application Germany, Feb. 9, 1961, Sch 29,210 4 Claims. (Cl. 11864) This invention relates to apparatus for coating printing cylinders with a light sensitive coating and in particular such an apparatus comprising a container for the coating fluid with an opening at the bottom, through which the printing cylinder is moved upwardly, wherein the bottom opening is sealed against the printing cylinder by means of a packing ring.

The provision of a uniform and blemish-free coating on a printing cylinder presents certain difiiculties. First, the cylinder and the coating fluid must be maintained at a constant and suitable temperature. Principally, however, a good coat depends upon holding the coating fluid in contact with each point along the length of a cylinder for an equal period of time and upon contacting the cylinder with blemish-free coating fluid.

As the printing cylinder is drawn through the coating fluid, the level drops continuously, so that the length of the contact surface becomes continuously smaller, and therefore also the time period during which the fluid remains in contact with the surface of the printing cylinder drops if the motion is of constant velocity.

Also in known apparatus, it is not assured that the printing cylinder and the fluid are held at a constant temperature or are brought to a suitable temperature.

In other apparatus, the pressure cylinders stand in the fluid and are slowly withdrawn. These devices, apart from the fact that no regular temperature is held or that the fluid and the cylinder are warmed to a suitable temperature, have the disadvantage that the coating fluid acts for a longer time on the lower part of the cylinder than on the upper part and thus there arises irregular action on the surface of the printing cylinder.

By means of the invention, all conditions are fulfilled which are necessary to provide a regular coating over the whole length of the tube. It provides a very simple solution to the problem of holding the level of the fluid steady, with the further advantage that the bubbles and impurities of the fluid, which usually collect in fluid vessels on the surface of the fluid, cannot come into contact with the printing cylinder.

According to the invention there is provided an apparatus for coating as a printing cylinder, comprising a container for the coating fluid, whose floor is provided with an opening having a sealing cuff through which the printing cylinder is drawn upwardly, characterised in that the fluid container is divided into two chambers by a separating cylinder arranged over the floor and around the floor opening, whereby the separating cylinder forms a gap, variable as far as complete cut off, serving as a connection between the two chambers.

The outer chamber holds the greater part of the coating fluid. The fluid flows through the gap between the container bottom and the separating cylinder into the inner chamber and thus to the surface of the printing cylinder. A portion of the fluid in the inner chamber is removed therefrom during the coating process by adherence of fluid to the cylinder. The gap between the two chambers may be set to provide that the flow of fluid into the inner chamber is substantially equal to the amount of fluid removed during coating. Since the fluid has a relatively high viscosity, the level of fluid in the "ice inner chamber remains lower than in the outer chamber, where it is correspondingly high. Further, only the fluid that is free from bubbles which rise to the top and bits of dirt which are found at the bottom of the container, reaches the surface of the cylinder.

Preferably, the separating cylinder is variable in height to alter the gap. Adjustability, or variation in height, of the cylinder may be achieved by employing any suitable means such as a screw or hydraulic jack to lift the separating cylinder.

In order to be able to completely close the inner chamber to entry of fluid when pouring in fluid before coating, and after coating is completed, a suitable wedge shaped groove is provided beneath the edge of the separating cylinder in the fioor of the container, into which the edge of the movable separating cylinder may lodge.

A heated cover is provided below the container which serves to heat the printing cylinder so that the latter has a constant temperature along its length.

The container and the heating cover are suitably double walled and connected to a hot water supply. Other methods of warming the container and the heating cover are of course equally possible.

In order that the invention may be well understood there will now be described one embodiment thereof, given by way of example only, reference being had to the accompanying drawing, in which:

FIGURE 1 is a longitudinal section view through a coating apparatus; and

FIGURE 2 shows the upper part of the same apparatus on a larger scale.

The container 1 is provided with an opening 2. On the edge 3 of the opening, an elastic cuff 4 is placed touching the outer surface of the cylinder 5 which is drawn upwards through the opening. Within the container there is a cylindrical separating wall 6 displaced from the inner edge of the floor opening, so that the fluid space is divided into two chambers 7, 8. The separating cylinder is liftable by means of suitable apparatus generally shown in FIG. 2 and its lower edge made wedge shaped. The wall 6 is displaced, or spaced, from the outer cylinder by any suitable means such as the member 12 shown in FIG. 2 which connects the wall to the lifting means. Corresponding to this is a wedge shaped groove 9 in the floor edge 3. The container is set in a bath 10 through which flows hot water or a suitable heating fluid. The container may be formed in one piece with the bath 10, as in this example. Beneath the container 1 and the bath 10 there is a double walled cylinder 11, which also has a flow of heating fluid through it, which warms the printing cylinder 5 to a constant temperature, and, during the process of coating which proceeds by drawing the cylinder in the direction of the arrow A, maintains it at a constant temperature.

The coating fluid in the container 7 flows through the regulable gap between the under edge of the separating cylinder 6 and the bottom 3 of the inner chamber 8, and is held therein at a constant level, while the printing cylinder 5 is drawn out upwards or is moved from underneath by means of a lifting apparatus.

I claim: I

1. A device for applying a coating of a light sensitive solution on a printing cylinder comprising in combination an open container, a first opening in the bottom of the container, said first opening allowing the passage therethrough of a printing cylinder to be coated, a flexible sealing ring having a second opening smaller than and aligned with said first opening, said sealing ring being attached to the bottom of the container and serving as a liquid seal between the container and a print ing cylinder to be coated, a tubular wall in the container, said wall defining an outside chamber and an inside circular chamber, said inside chamber being in alignment with and larger than said first opening in the bottom of the container, said wall being vertically movable to engage the bottom of said container thereby isolating said outside chamber from said inside chamber, and means to adjustably move said wall in a vertical direction to regulate the distance between the bottom of said wall and the container bottom, thereby providing an adjustable gap between said inside and outside chambers.

2. A device according to claim 1 further comprising heating means below the container to pre-heat a printing cylinder to be coated.

3. A device according to claim 1 wherein side and bottom walls defining the container are hollow and provided with inlet and outlet openings to provide a heating jacket for said container.

4. A device according to claim 3 wherein the hollow bottom wall defines a tubular opening below, aligned with and larger than said first opening in the container bottom.

References Cited by the Examiner UNITED STATES PATENTS 1,793,747 2/31 Prentice 222440 1,972,924 9/34 Dreyfus 118-68 2,129,249 9/38 Trahey 11865 2,159,297 5/39 Shover 11865 2,165,031 7/39 Brace 1l868 2,320,412 6/43 Cook 118-68 2,372,248 3/45 Bouton 118-405 2,602,959 7/52 Fenlin 118405 2,873,715 2/59 Signer 118405 2,978,349 4/61 Walsh et a1. 118405 FOREIGN PATENTS 17,794 7/ 97 Great Britain.

RICHARD D. NEVIUS, Primary Examiner. 

1. A DEVICE FOR APPLYING A COAT OF A LIGHT SENSITIVE SOLUTION ON A PRINTING CYLINDER COMPRISING IN COMBINATION AN OPEN CONTAINER, A FIRST OPENING IN THE BOTTOM OF THE CONTAINER, SAID FIRST OPENING ALLOWING THE PASSAGE THERETHROUGH OF A PRINTING CYLINDER TO BE COATED, A FLEXIBLE SEALING RING HAVING A SECOND OPENING SMALLER THAN AND ALIGNED WITH SAID OPENING, SAID SEALING RING BEING ATTACHED TO THE BOTTOM OF THE CONTAINER AND SERVING AS A LIQUID SEAL BETWEEN THE CONTAINER AND A PRINTING CYLINDER TO BE COATED, A TUBULAR WALL IN THE CONTAINER, SAID WALL DEFINING AN OUTSIDE CHAMBER AND AN INSIDE CIRCULAR CHAMBER, SAID INSIDE CHAMBER BEING IN ALIGNMENT 